In many respects, McCartney is spot on. When one of the big three
implements a fee or a change in their service, the other two
are quick to follow suit.

For instance, in early 2015, Delta changed its frequent-flyer
program from a mileage-based system to one based on revenue. This
means that instead of awarding passengers based on the number of
miles flown, the new system would calculate frequent-flyer miles
based on the amount of money spent.

"The big three airlines have dissolved into one big
homogeneous blob," industry analyst Henry Harteveldt, founder of
Atmosphere Research Group, a travel-industry survey and
consulting firm, told McCartney. "In the 1980s and 1990s
people said airlines were all alike. They were less all alike
then than they are now."

This sameness is simply a function of the market. The
airline industry is a highly capital-intensive business
that's incredibly sensitive to business cycles, currency
fluctuations, the general global economic climate, and
geopolitics. Although the three US mega-carriers are the most
profitable airlines in the world right now, none of the three are
that many years removed from financial ruin.

Since the great recession at the end of the last
decade, these airlines have turned the ability to
determine what the consumers need and what the consumer can do
without from an art into a precise science.

The reality is that the quality of the product offering is
determined by competition. For a business that requires so much
financial investment, any drastic improvement in quality
generally correlates with the need for a large cash injection. If
the airline doesn't want to eat into its margins, it will have to
raise prices.

This drives away value-conscious economy travelers — which
is essentially the whole back of the plane — and is what airlines
depend on to cover its costs. Conversely, none of the big
three can afford to fall behind in the quality of its premium
cabins. None of them want to risk losing the lucrative first- and
business-class flyers who help bolster
their profits.

So for better or for worse, US flyers are destined for more
of this sameness.